Why does the program that reads files still run very fast after clearing the page cache?

Test environment: Virtual Machine(Windows 11, VMware Workstation Pro), Ubuntu 22.04, mechanical hard drive. Use the following command to generate 1GB of test data: dd if=/dev/urandom of=test.data count=1M bs=1024 Clear the cache: sync; echo 3 > /proc/sys/vm/drop_caches Run: time cat test.data > /dev/null Execution time: real 0m14.814s user 0m0.011s sys 0m4.034s Clear the cache again: sync; echo 3 > /proc/sys/vm/drop_caches Run: time cat test.data > /dev/null Execution time: real 0m1.761s user 0m0.020s sys 0m1.679s Run immediately again (without clearing cache): time cat test.data > /dev/null Execution time: real 0m0.227s user 0m0.009s sys 0m0.218s After clearing the cache, I checked /proc/meminfo to confirm that the cache was indeed cleared. Why is the second run still significantly faster even after clearing the cache? Screenshot of the execution process: